1. Field of the Invention
The present specification relates generally to methods, software, devices, and systems that may be used for allocating bandwidth in a network.
2. Description of the Related Art
A wireless ad hoc network is typically defined as a collection of nodes that spontaneously form an autonomous, all-wireless infrastructure. In wireless ad hoc networks according to the related art, data is forwarded through multiple wireless hops before reaching an intended destination. In contrast, cellular networks typically provide wireless access that is restricted to a “last hop”.
A representative wireless ad hoc network 100 according to the related art is illustrated in FIG. 1. Nodes 20 in network 100 may be positioned in, for example, laptop computers, cellular phones, ships, automobiles, military vehicles, and/or airborne vehicles. By virtue of being included in mobile system, over time, each node 20 in wireless ad hoc network 100 may change its location and/or cease operating in network 100. Additional nodes, other than those illustrated in FIG. 1, may also join network 100 over time. Hence, the size and topography of network 100 varies over time.
Ad hoc wireless networks are attractive because they are flexible and fully distributed in the sense that they do not rely on a central authority to coordinate transmissions in the network. Such networks are also attractive because they typically have minimal deployment cost, can operate in unlicensed bands, allow for dynamically increasing capacity and coverage as more users are added to a network, and alleviate or eliminate the need for centralized network administration.
In addition, in certain currently available wireless ad hoc networks, such as network 100, users share a single broadcast channel via a random access protocol. Random access protocols are attractive because nodes can decide when to transmit based only on local information. On the other hand, these protocols lack coordination and, therefore can be susceptible to unpredictable interference due to, for example, transmission conflicts. This unpredictable interference renders random access protocols inappropriate for provision of Quality of Service (QoS) guarantees to the ad hoc network users. On the other hand, scheduled access methods such as TDMA achieve deterministic allocations via perfect coordination of transmissions but typically need global network knowledge to reach their goal.
At least in view of the above, what is needed are wireless ad hoc networks that are capable of providing strict bandwidth allocation and/or QoS guarantees to network users using only local information. What is also needed are methods of operating such networks. Further, what is needed are network devices capable of implementing these methods and computer-readable software products that may be used to operate the network devices.